Conveyors of the above-described kind are known in which, at least at the inside or the outside of the helically conveying path, or possibly both, the tiers of the conveyor belt are self-supporting, i.e. by means of spacers or the like any one helically extending tier is supported by the one below it. In this case, means are necessarily provided for supporting the lowermost tier, and this means in effect determines the pitch of the helical conveying path. A known means for this purpose is a supplementary conveyor, which optionally may also be employed to drive the lowermost tier of the stack thereof.
It is an object of this invention to provide an improved means of supporting the lowest tier of a helically extending conveyor belt.